1. Field Of the Invention
The invention pertains to nut connected couplings wherein a nut is rotatably mounted upon an end fitting for attachment of the end fitting upon a threaded adapter.
2. Description of the Related Art
The invention relates to a fluid coupling for connection to a flat face adapter wherein the adapter includes an outer sealing end surface, such end surface often being flat and radial. The coupling includes an end fitting having an outer surface having sealing means integral therewith, or associated therewith, such as an O-ring. An annular nut, rotatably mounted upon the end fitting includes a radial shoulder adapted to engage the nut radial shoulder, and the outer end of the nut is threaded, usually internally, whereby the nut may be threaded upon the adapter threads. As the nut is tightened the end fitting outer end is axially forced against the adapter outer end establishing a sealed fluid conducting relationship between the end fitting and the adapter. A typical connection of this type is shown in the assignee's U.S. Pat. No. 4,848,807 wherein a beam type lip seal is integrally defined upon the end fitting outer end for establishing a sealed relationship to the adapter outer end.
Couplings having integral sealing structure, such as a beam lip seal, are susceptible to seal damage when the coupling is uncoupled from an adapter. The coupling nut, when not threaded to an adapter, is free to axially move along the end fitting, and associated conduit, away from the end fitting outer end, and as the conduit and associated coupling are handled, moved, or otherwise manipulated the end fitting outer end and seal are totally exposed and will be damaged if engaged with a hard object. As metal sealing structure such as a beam lip seal is very accurately formed and the integrity of the lip seal surfaces is critical to establishing an effective seal, even a small nick or scratch occurring in the lip seal will prevent an effective fluid tight connection from being established between the end fitting and the adapter.
In the past, the ends of end fittings having beam lip seals, or the like, defined thereon, have been protected by removable caps, or the end of the end fitting may be dipped within a plastisol or other thick protective material which will harden. Such secondary protective procedures are expensive to apply, and require removal prior to use of the coupling. Further, a cap may be accidentally removed or knocked from the end fitting outer end exposing the seal.